Railway signaling



Feb. 10,1931.

J. M. PELIKAN RAILWAY SIGNALING 2 shets-sheet 1 Filed March 8, 1929 INVENTOR g; M-Pa/fkan Q-a-V.

A L. ATTORNEY Feb. 10, 1931 M P N 1,791,838

RAILWAY S IGNALING Filed March 8, 1929 2 Sheets-Sheet 2 ALI ATTORNEY Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE JOHN H. PELIKAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE N UNION SWITCH & SIGNAL COMPANY, OF SWISSYALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA RAILWAY SIGNALING Application filed March 8, 1929. Serial No. 345,368.

when placed end to end, with Fig. 1 on the left, constitute a diagrammatic view showing one form of apparatus embodying my invention.

Referring to the drawings, the reference character Y designates a stretch of single track connected with, successive passing'sidings, including sidings W and Z, by manually operable switcheswhich are designated A by reference letter F with distinguishing suffixes. Although one end only of siding W is shown in the drawing, it is to be understood that both ends of siding W are connected withstretch Y similarly to siding Z.

Rails 1 and 1a of the stretch Y are divided by insulated joints 2 into sections including sectionsA-B, B-C, C-D and D--E. Sid ing Z is connected by switches F2 and F3 with section D-E, which will therefore be referred to hereinafter as a siding section. Sections A-B, BC and CD are between siding section D-E and the siding section,

with which siding W is connected, and will therefore be referred to hereinafter as intermediate sections.

Each intermediate andYsiding section is provided with a direct cu rent track circuit to which current is supplied bya battery, designated by the reference letter Q with a distinguishing suflix, connected across the rails adjacent the east end of the section,

which end as shown in the drawings is toward the right. Each direct current track circuit includes a polarized direct current also provided with an alternating current track circuit to which current is supplied by a transformer, designated by the reference letter M with a distinguishing suflix,,connected across the rails adjacent the west end of the section. Each alternating current track circuit includes a three-position alternating current relay, designated by the reference letter G with a distinguishing sufiix, connected across the rails adjacent the east end of the section. Each of the relays G is of a type comprising two windings, 5 and 6. Winding 5 of each of the relays G is continuously supplied with alternating current from a source X by wires :0 and o.

. An overlap control relay is also connected across the rails of each intermediate section end which adjoins a siding'section. This relay is energized by the battery or. the transformer which is connected across the rails adjacent the same end of the same intermediate section. Since alternating current is supplied to the west end of each section, each R2 connected across the rails adjacent the west end of section AB is of the alternating current type. Relay R10 is a simila alternating, current overlap relay connected across the rails to the right of point E. Each alternating current overlap relay R is of a type comprising two windings 7 and 8. Winding 7 of each of these relays iscontinuously supplied with alternating current by wires :12 and 0. Each overlap relay adjacent the east end of an intermediate section, as for example relay N7 connected across the rails adjacent the east end of section CD, issupplied with direct current from the adjacentbattery such as Q7, and is therefore of the direct currenttype.

Resistances 3 are connected in series with the secondary windings of transformers M and with the windings 6 of relays G and with the windings 8 of relays R2 and R10 to obstruct the flow of direct current from bat: teries Q through the alternating current apparatus. Similarly, the impedances 4 are connected in series with batteries Q and with the windings of relays H and N7 to impede .the flowof alternating current from transformers M through ratus.

Each of the switches F operates a contact the direct current appa- -9 which is closed only while the respective clude a" contact 9 of each switch in the same siding section.

Two signals governing in opposite directions, respectively, and designated by the reference letter S with distinguishing suflixes, and which as here shownare of the semabe referred to as the proceed and caution in-- dications, respectively.

Two-position slow-release rela s,. desig nated by the reference characters 1, P7 and P9, are placed ad acent locations A, and E, respectively. Each of these relays is energized by current from wires :12 and '0 when the adjacent alternating current track relay is energized in either its normal or its reverse direction.

Directional control stick relays, designated by the references T3 and T4, respectively,

adj acent location B, are employed for select ing between the signal controls for opposing and following trafiic moves. Slow release relays L3 and L4 are controlled by track relays G3 and H4, respectively, and by [stick relays T4 and T3, respectively.

Directional control stick relays T5 and T6, adjacent location C, are controlled similarly to relays T3 and T4. Slow release relays L5 and L6, also adjacent location C, are C011- trolled similarly to relays L3 and L4.

Having thus described, in general, the location and arrangement of the various parts comprising my invention, I will now describe in detail the operation of the appa ratus.

As shown in the drawings, all parts are in their normal condition, that is, each of the sections A-B, B-C, C-D and DE is unoccupied, each of the switches F is in its normal position, each of the signals S 18 indicating proceed, each intermediatesection between section D-E and the next siding east of siding Z is unoccupied, and each section between section A-B and the next siding west of siding W is unoccupied. With these various sections unoccupied, each of the track relays G and H, shown in the drawings, 1S

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energized in its normal direction, and overlap relays R2, R10 and N7 are energized;

The circuit by which cmhsicnhcr M2 is controlled, for energizing winding 6 of relay .G3 in the normal direction, passes from wire :I:, through contact 56 of relay G1, wire 57, contact 58a of relay Pl, wire 59, primary winding of transformer M2, Wire 60, contact 61a of relay P1, wire 62, and contact 63 of relay G1 to wire 0. Transformer M4, now energizing winding 6 of relay G5 in the normal direction, is supplied with current by a circuit passing from wire as, through contact 64 of relay G3, wire 65, primary winding of transformer M4, wire 66, and contact 67 of relay G3 to wire 0. Transformer. M6, now energizing winding 6 of relay G7 in the normal direction, is supplied with current, similarly to transformer M4, by a circuit passing from wire a:, through contact 72 of relay G5, wire 73, primary winding of transformer M6, wire 74, and contact 75 of relay G5 to wire 0. Transformer M8, now energizing winding 6 of relay G9 in the normal direction, is supplied with current by a circuit passin from wire :12, through contact of relay G wire 81, contact 82a of relay P7, wire 83, contact 84 of relay N7, wire 85, primary winding of transformer M8, wire 86, contact 87 of relay N7, wire 88, contact 89a of relay P7 wire :90, and contact 91 of relay G7 to wire 0. Transformer M10 is supplied withcurrent by a circuit which is similar to that already traced for transformer M2. Relay G1 is energized in the normal direction by a transformer which is controlled similarly to transformer MS as already described.

Relay H2 is now energized in the normal direction by a circuit which passes from b'at tery Q3, through wire 34, contact 35 of relay H4, wires 36 and 37, rail 1, impedance 4, winding of relay H2, rail 1a, impedance 4, wire 38, contact 39 of relay H4 and wire 40 back to battery Q3. Relay -H4 is energized in the normal direction by a circuit passing from battery Q5, through wire 21, contact 22 of relay H6, wire 23, rail 1, impedance 4, winding of relay'H4, rail 1a, impedance 4, wires 24 and 25, contact 26 of relay H6, and wire 27 back to battery Q5. Relay H6 is energized in its normal direction by a circuit passing from battery Q7, through contact 20a of relay H8, impedance 4, rail 1a, winding of relay H6, impedance 4, rail 1, and contact 19a of relay H8 back to battery Q7. Relay H8 is energized in its normal direction by a circuit passing from battery Q9, through contact 10a of relay H10, wire 11, contact 12 of relay R10, wire 13, contact 9 of switch F3, rail 1, winding of relay H8, impedance 4, contact 9 of switch F2, rail 1a, wire 14, impedance 4, wire 15, contact 16 of relay R10, wire 17, and contact 18a of relay H10 back to battery Q9. Relay H10 is energized in its normal direction by a circuit which is exactly similar to the circuit already traced for relay H2. Battery Q1 supplies current to the siding section at siding W by a circuit which is exactly similar to the circuit by which battery Q9 supplies current to section DE.

The energization of winding 8 of overlap relay R2 is controlled by the same circuit for transformer M2 as alread traced for the control of the energization 0 winding 6 of relay G3. The energization of winding 8 of relay R10 is controlled by a similar circuit including the primary winding of transformer M10. The circuit by which overlap relay N7 is energized passes from battery Q7, through contact 20a of relay H8, impedance 4, winding of relay N7, impedance 4, and contact 19a of relay H8 back'to battery Q7.

With relay G7 energized, relay P7 is energized by its circuit passing from wire a, through contact 102 of relay G7, and winding of relay P7 to wire 0. Relays P1 and P9 are energized by similar circults through contacts 160 and 101 of relays G1 and G9, respectively.

Relay L3 is energized by a circuit passing from wire a:, through back contact 134 of relay T4, wire 135, contact 136 of relay G3, wire 137, and the winding of relay L3 to wire 0. Relay L4 is energized by a circuit passing from wire :12, through the winding of relay L4, wire 131, contact 132 of relay H4, wire 133, and back contact 71?) of relay T3 to wire 0. Relays L5 and L6 are energized by circuits similar, respectively, to the circuits just traced for relays L3 and L4.

\Vith relay G1 energized in its normal direction and with relay P1 energized, the arm of signal S1 is held in its proceed position by its circuit passing from 'wire :12, 'throu h contact 185 of relay P1, wire 186, contact 18 a of relay G1, and the o crating mechanism of si nal S1 to wire 0. Vith rela H2 energize in its normal direction, t e arm of signal S2 is held in its proceed position by a circuit passing from wire :12, through contacts 183 and 184a of relay H2, and the operating mechanism of signal S2 to wire 0. The arms of signals S9 and S10 are retained in their proceed position by circuits similar, respectively, to the circuits just traced for slgnals S1 and S2. I

The arm of signal S3 is held in its proceed position by its circuit passing from wire :22, through contact 180 of relay L3, wire 181, contact 182a of relay G3, and the operating mechanism of signal S3 to wire 0. The arm of signal S4 is held in its proceed position by its circuit passingfrom wire av, through contact 177 of relay L4, wire 178, contact 179a of relay H4, and the operating mechanism of signal S4 to wire 0. The arms of signals S5 and S6 are held in their proceed positions by their circuits which are similar, respectively, to the circuits S3 and S4.

just traced for signals The arm'of signal S7 vis held in its proceed position by a circuit passin from wire :10, through contact 168 of relay 7, wire 169, contact 170a of relay G7, and the operating mechanism of signal S7 to wire 0. The arm of signal S8 is held in its proceed position by a circuit passing from wire w, through contacts 166 and 167a of relay H8, and the operating mechanism of signal S8 to wire 0.

I will now assume that a westbound train enters the first intermediate section west of the first siding section east of section DE.' Relay H10 is thereby de-cnergized in the same way that relay H2 is de-energized when a Westbound train enters section CD as will be described hereinafter. When the westbound train, upon proceeding further, enters the section ad'oining the east end of section D--E, relay I-llO continues de-energized but relay R10, being supplied with current from the secondary winding of the adjacent transformer M10, does not become sufficiently deenergized to open its contacts until the approaching westbound train has proceeded some distance into the section adjoining the east end of section D-E. From the time relay H10 becomes de-energized until relay R10 becomes de-energized, direct current of reverse polarity is supplied to section D-E by a circuitpassing from battery Q9, through contact 106 of relay H10, wire 17, contact 16 of relay R10, wire 15, impedance 4, wire 14, rail 1a of section D-E, contact 9 of switch F2, impedance 4, winding of relay H8, rail 1 of section D-E, contact 9 of switch F3, wire 13, contact 12 of relay R10, wire 11, and con tact 18b of relay H10, back .to battery Q9.

Vhen relay H10 becomes de-energized the arm of signal S10 moves to its sto position. When relay H8 becomes energized ily current of reverse olarity supplied to section DE, the arm of tion position by its circuit passing from Wire :0, through contacts 166 and 167 b of relay H8, and the operating mechanism of signal S8 to wire o.' i a 4 The westbound train, upon approaching nearer to signal S10, de-energizes relay R10 which then opens, at its contacts 12 and 16, age glirect current track circuit for section moves to its stop'position due to the o ning of contact 166 of relay H8. With re ay H8 de-energized, direct current of reverse polarity is supplied by battery Q7, through contacts 19b and 20b of relay H8, to section CD, causing relay H6 to be energized in its reverse direction. With relay H6 energized in its reverse direction, signal S6 is operated to its caution position by its circuit passing from wire m, through contact 171 of relay L6, contact 17 3b of relay H6, and the operating mechanism of signal S6 to wire 0.

The train, upon entering section D-E, deenergizes relay G9 as well as relay H8, theresignal S8 is operated to its cau- The arm of signal S8 thereupon by causing the arm of signal S9 to assume its stop position. When the train has completely passed both insulated joints 2 at location E, relay H10 will again become energized in the normal direction so that the arm of signal S10 will be returned to its proceed osition.

The train, upon entering section D, deenergizes relays H6 and G7 thereby causing the arms of signals S6 and S7 to assume the stop position. Relay H6, by opening its contact 104, de-energizes relay L6. Relay H6, also upon becoming de-energized, opens, at its contacts 22 and 26, the direct current track, circuit previously traced for section B-C, thereby causing relay H4 to become de-energized. Relay H4, upon becoming de-energized, .causes the arm of signal S4 to assume its stop position. Re lay H4, also upon becoming tie-energized, opens, at its contacts and 39, the direct current track circuit previously traced for section AB, causing the de-energization of relay H2, which in turn causes the arm of signal S2 to assume its stop position. Relay P7 will be de-energized because its circuit is open at contact 102 of relay G7 Relay L6 will be de-energized because its circuit is open at contact 104 of relay H6.

Relay H8 becomes energized in normal direction as soon as the train passes location D, causing the arm of signal S8 to again assume its proceed position. When the train has proceeded a suflicient distance beyond location D to permit relay N7 to again become energized by, battery Q7, alternating current of reverse polarity is supplied to section I)E due to the reverse energization of the primary winding of transformer M8 by a circuit passing from wire it, through contact 895 of relay P7, wire 88, contact 87 of relay N7, wire 86, primary winding of transformer M8, wire 85, contact 84 of relay N7, wire 83, and contact 826 of relay P7 to wire 0. Relay G9 is now energized in its reverse direction, causing the arm of signal S9 to be operated to its caution position by a circuit passing from terminal w, throng contact 161 of relay P9, wire 162, contact 163?) of relay G9, and the operating mechanism of signal S9 to wire 0.

As the train starts into section BC, relay G5 becomes de-energized, closing its contact 121 and opening itscontact 108 in the control of relay L5. Relay L5, being of a slow releasingtype, does not open its front contacts until after the lapse of a brief period of time following the closing of contact 121 of relay G5. Relay T5 therefore becomes energized by its pick-up circuit passing from wire w,through contact 121 of relay G5, wire 122, contact 127 of relay L5, wire 128, contact 129 of relay L6, wire 130, and the wlnding of relay T5 to wire 0. Relay T5, upon becoming energized, completes 1ts stlck C11- cuit passing from wire :12, through contact 121 of relay G5, wire 122, contact 123 of relay T5, wire 124, contact 125 of relay T6, wire 126, and the winding of relay T5 to wire 0. Relay T5 then continues energized by its stick circuit as long as the train occupies sectiondBC causing relay G5 to be de-energize With relay T5 thus energized, alternating current of reverse polarity is supplied to section CD as soon as the train has C011]- pletely passed location C. This is accomplished by the energization of the primary winding of transformer M6 by its circuit passing from wire as, through contact 76 of relay T5, wires 77 and 74, primary winding of transformer M6, wires 7 3 and 78, and contact 79a of relay T5 to wire 0. Relay G7 therefore becomes energized in its reverse direction, causing the arm of signal S7 to be operated to its caution position by its cir cuit passing from wire 00, through contact 168 of relay P7, wire 169, contact 170?) of relay G7, and the oprating mechanism of signal S7 to wire 0. Also, with relay G7 energized, relay P7 becomes energized by its circuit through contact 102 of relay G7. Current of normal polarity is now supplied to transformer M8 by its circuit passing from wire as, through contact 80 of relay G7, wire 81, contact 82a of relay P7 wire 83, contact 84 of relay N7, wire 85, the primary winding of transformer M8, Wire 86, contact 87 of relay N7, wire 88, contact 89a of relay P7, wire 90, and contact 91 of relay G7 to wire 0. Relay G9 is now energized in its normal direction, causing the arm of signal S9 to be returned to its proceed position. Relay H6 is also energized in its normal direction when the train leaves section CD, causing the arm of signal S6 to be returned to its proceed position.

As the train starts into section AB, relay T3 becomes energized by its pick-up circuit which is-slmilar to that already traced for relay T5. A stick circuit for relay T3, similar to the stick circuit traced for relay T5, then becomes closed, causing relay T3 to continue energized while the train is proceeding through section AB.

When the train leaves section H-C, alternating current of reverse polarity is supplied to section BC in a manner similar to that described for section CD when the train passes location C. The arm of signal S5 is then operated to its caution position, and the arm of signal S7 is operated to its proceed position. Direct current of normal polarity is now supplied to section BC, and hence the arm of signal S4 is returned to its proceed position.

When the train starts past location A, relay Gl becomes de-energized, causing signal S1 to indicate stop. When the train leaves section AB, current of reverse polarity is supplied to the primary winding of transformer M2 by its circuit passing from wire a through contact 61?) of relayPl, wire '60, primary winding of transformer M2, wire 59, and contact 586 of relay P1 to wire 0. Relay G3 is therefore energized in its reverse direction, causing signal S3 to beoperated to its caution position andsignal S5 to be operated to its proceed position. Direct current of normal polarity is supplied to section AB by battery Q3, and hence relay H2 is energized in its normal direction, causing signal S2 to indicate proceed.

I will now assume that all parts are again in their normal condition, as previously described, and that an eastbound train is to proceed from siding W. A trainman therefore reverses switch F1, which now opens its contact 9, causing relay G1 to be de-energized. The arm of signal S1 is therefore operated to its stop position, and alternating current of reverse polarity is supplied to section A-B as previously described, causing the arm of signal S3 to be operated to the caution position.

The. train, upon entering section AB,

de-energizes relays H2 and G3, causing signals S2 and S3 to indicate stop. Relay T3 as well as relay G3 being now de-energized,

the alternating current track circuit for section BC is opened, causing relay G5 to become de-energized and signal S5 to indicate stop. Relay G5 becoming de-ener'gized while relay T5 is de-energized, the alternating current track circuit for section CD is also opened, causing relay G7 to become deenergized and signal S7 'to indicate stop. With relay G7 de-energized, current of reverse polarity is supplied to the alternating current track circuit for section DE, causing relay G9 to' be energized in its reverse direction, which in turn causes signal S9 to indicate caution.

As the train starts into section B-C, re-

' lay T4 becomes energized by its pick-up circuit passing from wire :12, through contact .138 of relay L3, wire 139, contact 140 of relay L4, wire 141, contact 142 of relay H4, wire 143, and the winding of relay T4'to wire 0. Relay T4, upon becoming energized, closes its contact 148, thereby completing'its stick circuit passing from wire a, through contact 144 of relay H4, wire 145, contact 146 of relay T3, wire 147, contact 148, and the windin of relay T4 to wire 0. After the lapse of a brief period of time following the de-energization of relay H4, slow-releasin relayi L4 opens its contact 140a in'the plek-up circuit for relay T4, but

relay T4 then continues energized by its stick circuit while the train is proceeding through section BC.

With relay T4 energized, direct current of reverse polarity is supplied to section AB as soon as the train has completelypassed location B, by a circuit passing from batter Q3, through wire 41, contact'42 of relay impedance 4, rail '1 of section AB, wires 37 and 44, contact 45 of relay T4, and wire "46 back to battery Q3. R'elay H2 is thus T4. Relay T6, upon becoming energize closes its stick circuit which is similar to that traced for relay T4.

As the train leaves section B-C, signal S4 becomes operated to its caution position in a manner similar to that in which signal S2 was operated to its caution position when the train left section AB. With relay H4 energized in its reverse position when the train has left section B-O, direct current of normal polarity is supplied to section AB by battery Q3 through contacts 35 and 39 of relay H4. Relay H2 is then energized in its normal direction, causing the arm' of signal S2 to be operated to its proceed position.

From the foregoing description and the accompanying drawings, it is clear that my present invention by employing a direct track circuit and an alternating current track circuit for each section, provides, without the use of line control circuits, the directional control previously accomplished in absolute permissive block signaling s sterns by means of line control circuits with a single track circuit for' each track section.-

Although I have herein. shown and described only one form of railway signalling apparatus embodying m invention, it is understood that various 0 anges and modifi= cations may be made therein within the scope of the appended claims without departing from the spirit and scope of my 1nvention.

Havin thus described .my invention, what I c aim is:-

1. In combination, a section of railway track, a track circuit including the rails of said section and a source of current as well as a relay responsive to the current supplied to said-circuit by said source, a second track circuit including the rails of said section and 4, wires 43 and 38, impedance 4, mil 1a of section AB, winding of relay H2,

controlled by said first relay, and a signal governing traflic in the opposite direction through said section and controlled by said second relay. v

2. In combination, a section of railway track, a track circuit including the rails of said section and a source otf'current as well as a relay responsive to the current supplied to said circuit by said'source, a second track circuit including the rails of said section and a second source of current as well as a second relay responsive to the current supplied to said second circuit by said second source, means for impeding the fiow of current from said first source through said second relay,

means for impeding the fiow of current from said second source through said first relay, a first device for governing traflic in one direction through said section and controlled by said first relay, and a second device governing traflic in the other direction through said section and controlled by said second relay.

3. In combination, a section of railway track, a track circuit-including the rails of said section and a source of current as well as a relayresponsive to the current supplied to said clrcuit by said source, a second track .circuit including the rails of said section and a second source of current as well as a,

second relay responsive to the current supplied to said secondcircuit by said second source, means for impeding the flow of current from said first source through said second relay, a first device forgoverning traflic in one direction throu' h said section and controlled by said first re ay, and a second device governing trafiic in the other direction through said section and controlled by said second relay. 1

4. In combination, a section of railway track, a relay and a source of current connected across the rails adjacent one end of said section and a second relay and a second source of current connected across the rails adjacent the opposite end of said section, the

second relay being responsive to current from the first source but not to current from the second source, and the first relay being responsive to current from the second source) but not to current from the first source, a first device for governing trafiic in one-direction through said section and controlled by said first relay, and a seconrlI-d-evice governing traflie in the,.other direc ion through said sectionandcontrolled by said second relay.

-=;5..,In combination, a section of.-railway track, .a, ;relayand a-source ofcurrent connected across the rails adjacent one. end of 'saidsection and-a second relay and a second sourceaof current connected across the rails adjacent the" opposite end' of said"section, means for contemporaneously and selectively energizing said first and second relays by curfic governing device controlled by said first relay, and' a second trafiic governing device controlled by said second relay. b

6. In combination, a section of railway track, a relay and a source of current connected across the rails adjacent one end of said section and a second relay and a second source of current connected across the rails adjacent the opposite end of said section, the second relay being responsive to current from the first source but not to current from the second source, and the first relay being responsive to current from the second source but not to current from the first source, a first device for governing trafiic in one direction through said section and a second device for governing traffic in the opposite direction through said section, means for controlling said first device by said first relay, and means for controlling said second device by said second relay.

7. In combination, a section of railway track, a track circuit including the rails of said section and a source of current as well as a relay responsive to the current supplied to said circuit by said source, a second track circuit including the rails of said section and a second relay as well as a second source supplying said second track circuit with current to which said second relay but not said first relay is responsive, a first device for governing traflic in one direction through said section and a second device for governing trafiic in the opposite direction through said section, means for controlling said first device by said first relay, and means for controlling said second device by said second relay.

8. In combination, a section of railway track, an alternating current relay and a direct current source connected across the rails adjacent one end of said section and a direct current relay and an alternating current source connected across the rails adjacent the opposite end of said section, means for controlling said alternating current relay by current from said alternating current source, means for, controlling said direct. current relay by current from said direct current source, a first trafiic governing device controlled by said alternating current relay, and a second traflic governing device controlled by said direct current relay.

9. In combination, a section of railway track, an alternating current track circuit for said section, a direct current track circuit for said section, means for controlling traflic in one direction through said section by said alternating current track circuit, and means for controlling traffic in the opposite direction through said section by said direct cur-T rent track circuit. 10. A railway trafiic controlling system comprising a plurality of successive sections of railway track, an alternating current track circuit for-each of said sections,a direct current track circuit for each of said sections, means for controlling trailic in one direction over said track by said alternating current track circuits, and means for controlling trafiic in the opposite direction over said track by said direct current track circuits.

11. A railway trafiic controlling system comprising a plurality of successive sections of railway track, an alternating current track circuit for each of said sections, a direct current track circuit for each of said sections, a plurality of signals spaced along said track for governing trafiic in one direction, a plurality of signals spaced' along said track for governing traflic in the opposite direction, means for controlling the signals for said first traflic direction by said alternating current track circuits, and means for controlling the signals for said opposite traffic direction by said direct current track circuits.

12. In an. absolute permissive block signaling system, a section of railway track, a second section of track one end of which adjoins one end of said first section, a signal adjacent the opposite end of saidfirst section for governing the movement of traffic through said first section toward said second section, a signal adjacent the opposite end of said second section for governing the movement of trafiic through said second section toward said first section, a direct current relay connected across the rails of said first section adjacent said first signal, means for supplying said first section with alternating current, an alternating current relay and a direct current source connected across the rails of said second section adjacent said second signal, a second alternating current relay connected across the rails of said first section 4 alternating current relay and by said second direct current relay and arranged to become energized when traflic moves from said first to said second section, means for supplying direct current to the rails of said first section through contacts of said second direct current relay in multiple with contacts of said second stick relay, means for supplying alternating current to the rails of said second secs tion as controlled by contacts of said second alternating current relay in multiple with contacts of said first stick relay, meansfor controlling said first signal by said first di- JOHN M. PELIKAN. 

